Setting out 12042018

There are no fixed procedures according to which setting out has to be
done since each case can be different.
However, to be able to form an idea of the different measurement activities
and the methods and instruments which can be chosen in each case, the
main parts of a setting out procedure can be described as follows:
1. Planning for setting out
2. Initial setting out
3. Setting out first stage
4. Setting out second stage
5. Setting out levels
6. Transfer of points and lines
7. Measuring with a tape
8. The measuring of distances with EDM instruments
9. Application of International Standard for setting out

• Setting out is the process of
extracting information from the
construction drawings, and
pegs, profiles or other marks
are then set to control the
construction works and to
ensure that each features in
the drawings are constructed in
the right position and to the
correct level.
This can be in the form of
building corners, sewers,
earthworks, road works, steel
structures or line works

• Setting out is the process of
extracting information from the
construction drawings, and
pegs, profiles or other marks
are then set to control the
construction works and to
ensure that each features in
the drawings are constructed in
the right position and to the
correct level.
• According to ISO_7078: 1985
Building Construction –
Procedures for Setting out,
Measurement & Surveying –
Vocabulary & Guidance Notes:
Setting out is defined as the
establishment of marks & lines
to define the position & level of
elements of the construction
work so that works may
proceed with reference to
them.
• This process is contrasted with
the purpose of “surveying”
which is to determine the
positions of existing features on
site by measurement.

• Often used definition: setting
out is the reverse of
“surveying”, i.e. surveying is a
process of producing a plan or
a map of a particular area,
while, setting out begins with
the plan and ends with the
various elements of an
engineering project correctly
positioned in the area. (Uren, J.
et al., 2006)
• Good work practices &
techniques in setting out is
essential to minimize errors &
to ensure the construction
process proceeds smoothly.
• Good knowledge is vital, as the
setting out phase is one of the
most important stages in any
civil engineering construction
project.
• Mistakes in setting out can be
costly and should be borne by
the contractor.

• Even though the “surveying”
and “setting out” are opposite
processes to each other, but
the techniques and instruments
used for both processes are
identical.
• Among all parties who are
involved in construction works,
the “setting out” is the
responsibility of the contractor.
• Three main principles of setting
out operations:
1. Horizontal control
technique
2. Vertical control technique
3. Positioning technique
• Two main aims when
undertaking setting out
operation:
1. Various elements of the
scheme in the construction
drawings must be correct
in all three dimensions,
both relatively and
absolutely, that is each
must be in its correct size,
plan position and correct
reduced level.
2. Once setting out begins, it
must proceed quickly with
little or no delay in order
that the works can proceed
smoothly & the cost can be
minimized.

• Overall, there are three stages
of setting out need to be
carried out in construction
works:
1. Initial setting out – limits of
work and site
2. Stage 1: Setting out of
foundation and sewer
pipeline;
3. Stage 2: Setting out the
design points.
• Example of specification with
regards to “setting out” in
Construction Drawing

works:
work and site
pipeline;
design points.
• Example of Setting Out
Drawing in Construction
Drawing

works:
work and site
pipeline;
design points.
Drawing
• To set out the limits of works
and site, at least two
coordinate points are needed –
i.e. setting out coordinate
points.

• Overall, there are two stages of
setting out need to be carried
out in construction works:
1. Stage 1: Setting out limits
of work and site;
design points.
• Example of General Notes with
regards to “Setting Out” in
Drawing
and site, at least to coordinate
points are needed – i.e. setting
out coordinate points.

and site, at least to coordinate
points are needed – i.e. setting
out coordinate points.
• BS 5964-1:1990 is concerned
with the complete range of
setting-out on building sites.
• In summary, BS has
highlighted three-stage order of
reference systems commonly
adopted for large and complex
building projects.
1. Primary system
2. Secondary system
3. Position points
• Position points give the
location of the details of the
building.
works:
work and site
pipeline;
design points.
Drawing

• 3-stage order of reference
systems commonly adopted
for large and complex building
projects.
1. Primary system
2. Secondary system
3. Position points
• Position points give the
location of the details of the
building.
• 3 main principles of setting out
operations:
1. Horizontal control
technique
2. Vertical control technique
3. Positioning technique
• 3 stages of setting out need to
be carried out in construction
works:
work and site
pipeline;
design points.

• A reconnaissance of the site
and planning of the setting out
are essential.
• Based on the construction
drawing, a suitable reference
system should be selected and
established.
• A suitable reference system
selected will depend on:
1. The shape and size of the
site;
2. The positions of any
existing buildings or
obstructions.
3. The positions of the
proposed building and
ancillary works ;
4. The sequence of
excavation and
construction woks.

• The chosen reference system should be such that redundant
observations are possible and that the measuring points can be
referred to during construction.
• The position of the main ground station should be chosen and
protected such that they are at a min. risk to damage or movement
and unobstructed lines of sight can be maintained.

• Location grids are used to
assist the planning authorities
and designers in plotting the
location of boundaries,
buildings, roads, underground
utilities or other features.
• If the building to be set out, it is
important to mark on the plan
of the building site the
approximate position of the
structural grid or site grid.
• Site grids can be considered
as the transfer of the location
grid from the plan or drawing to
the site by setting out.
• Structural grid are used by
designers to define the position
of structural elements, usually
their center-line.

• The marking of site clearance
and excavation areas.
• Methods of setting out:
1. Polar setting out method
2. Intersection method
3. Offset method
4. Method of free station
points
• Establish permanent point
• Position of permanent point
• Establish benchmark

• In practice, 1st stage setting out
involves the use of many
horizontal and vertical control
techniques.
• The purpose of this stage is to
locate the boundaries of the
works in their correct position
on the ground surface and to
define major elements.
• In order to do this, horizontal
and vertical control points must
be established on or near the
site.
• 2nd stage setting out continues
from the 1st stage setting out.
• E.g.: Beginning at the ground
floor slab, or road sub-base
level, etc.
• Up to this point, all the control
points will be outside the main
construction.
• E.g.: The pegs defining building
corners, center lines and so on
will be knocked out during
excavation works and only the
original control points will be
undisturbed.

• Establish horizontal control
points in the E and N
coordinates points on the site
so that the design points for
each of the elements of the
scheme in the construction
drawings can be correctly fixed
in position;
• Two factors to consider in
establishing horizontal control
points:
1. The control points should
be located through out the
site in order all the design
points can be fixed from at
least two of them so that
the work can be
independently checked;
2. The design points must be
set out to the accuracy
stated in the specifications.

• The construction and protection
of control points is very
important.
• Wooden pegs are usually used
for non-permanent marking
(control points).
• Concrete mark is used for
permanent marking (control
point).
• Horizontal control points can
be:
1. Baselines
2. Reference grid
3. Offset pegs

• A baseline is a line running
between two points of a known
position.
• Any baseline required to set
out a project should be
specified on the setting out
plan/drawing by the designer
and included in the contract.
• Baseline can take many forms:
1. Two specified points
joined;
2. Run between two
buildings;
3. Mark the boundary with an
existing building/
development;
4. Mark the center line for a
new road;

• A control grid enables points
to be set over a large area.
• Several different grids can
be used in setting out:
– (1) grid survey;
– (2) grid site;
– (3) structural grid;
– (4) grid secondary.
is drawn on the survey plan from the
original traverse or network. The grid
points have known “eastings” and
“northings” related either to some arbitrary
origin or to the national grid.

– (2) grid site;

– (2) grid site;
is used by the designer. It is usually related
in some way to the survey grid and should,
if possible, actually be the survey grid, the
advantage of this being that if the original
control stations have been permanently
marked then the design points will be on
the same coordinate system and setting
out is greatly simplified.

• Several different grids can be
used in setting out:
– (2) grid site;
– (3) structural
grid;
The structural grid is established around a
particular building or structure which
contains much detail such as columns,
which cannot be set out with sufficient
accuracy from the grid site.

– (2) grid site;
– (3) structural
grid;

– (2) grid site;
– (4) grid
secondary.
The secondary grid is established inside
the structure from the structural grid when
it is no longer possible to use the structural
grid to establish internal features of the
building – as the vision becomes obscured.

• Whether used in the form of a
baseline or a grid, the
horizontal control points are
used to establish design points
on the proposed structure.
• Once excavations for the
foundations begin, the corner
pegs will be lost. To avoid this
extra pegs, offset pegs are
used.

• In order the design points can be positioned at their correct levels,
vertical control points of known elevation relative to some specified
vertical datum are established.
• Some vertical control techniques:
1. TBM
2. Sight rails
3. Travellers and boning rods
4. Slope rails or batter boards

• TBM:
The positions of TBMs should be
fixed during the initial
reconnaissance so that their
construction can be completed in
good time and they can be
allowed to settle before levelling
them in. In practice, 20mm
diameter steel bolts and 100mm
long, driven into existing steps,
ledges, footpaths etc. are ideal.

• Sight rail:
These consist of a horizontal
timber cross piece nailed to a
single upright or a pair of uprights
driven into the ground. The upper
edge of the cross piece is set to a
convenient height above the
required plane of the structure,
usually to the nearest 100mm, and
should be a height above ground to
ensure convenient alignment by
eye with the upper edge.

• Sight rail:
Sight rails are usually offset 2 or 3 m
at right angles to construction lines to
avoid them being damaged as
excavations proceed.

• Travellers and boning rods:
– A traveller is similar in appearance to a sight rail on a single
support and is portable. The length of the upper edge to its
base should be a convenient dimension to the nearest half
meter.
– Travellers are used in conjunction with sight rails. The sight
rails are set some convenient value above the required
plane and the travellers are constructed so that their length
is equal to this value.
– As excavation works proceeds, the traveller is sighted in
between the sight rails and used to monitor the cutting and
filling.

• Slope rails or batter boards:
– For controlling side slopes on embankments and cuttings
slope rails are used.
– For an embankment the slope rails usually define a plane
parallel to the slope of the embankment offset by a
convenient distance:

• Before the excavation for the proposed foundation is commenced, the site
shall be cleared of vegetation, brushwood, stumps of trees, debris, etc.
• Next is to set out a baseline for the work.
• For setting out the foundations of small buildings, the centre line of the
longest outer wall of the building is first marked on the ground by
stretching a string between wooden or mild steel pegs driven at the ends.
• For accurate work, nails can be fixed at the centre of the pegs.
• Two pegs, one on either side of the central peg, are driven at each end of
the line. Each peg is equidistant from the central peg, and the distance
between the outer pegs corresponds to the width of foundation trench to
be excavated.
• Each peg may project about 25 to 50 mm above ground level and may be
driven at a distance of about 2 m from the edge of excavation so that they
are not disturbed.

• When string is stretched joining the corresponding pegs (say 2-2) at the
two extremities of the line, the boundary of the trench to be excavated can
be marked on the ground with dry lime powder.
• The centre lines of other walls, which are perpendicular to the long wall,
are then marked by setting out right angles.
• A right angle can be set out by forming a triangle with 3, 4 and 5 units
long.
• These dimensions should be measured with the help of a steel tape.
Alternatively, a theodolite or prismatic compass may be used for setting
out right angles.
• Similarly, outer lines of the foundation trench of each cross-wall can be set
out, as shown in the following figure.

The six corners of a proposed L shaped excavation shown in Figure 1 (a)
below have been set out on site.
Figure 1 (a)
Offset pegs have been established to help define the sides of the excavation.

The proposed formation level of the surface of the excavation at point R is
95.72 m. The surface is to fall at 1 in 150 from R to W and is to rise at a slope
of 1 in 100 at right angle to the line RW.
Figure 1 (b)
The cross-sections for lines P1RWP2 and P4UTP3 are as depicted in Figure 1
(b) and (c), respectively.

To help with excavation site, sight rails are to be erected above the offset
pegs for use with a 2 m traveler. Given the reduced levels of the offset pegs,
calculate the heights of the sight rails to be used at P1, P2, P3 and P4.
Figure 1 (c)

Solution for line P1RWP2
Formation level at P1 = 95.72 + (3/150) = 95.74m
Formation level at P2 = 95.72 – (48/150) = 95.40m
For offset peg P1
Required top of sight rail level = 95.74 + 2.00 = 97.74 m
Actual of peg level = 96.95 m
Therefore, distance above P1 = 0.79 m
For offset peg P2
Required top of sight rail level = 95.40 + 2.00 = 97.40 m
Actual of peg level = 96.45 m
Therefore, distance above P2 = 0.95 m

Solution for line P4UTP3
Formation level at Z = 95.72 - (15/150) = 95.62m
Formation level at P3 = 95.62 – (28/100) = 95.90m
Formation level at P4 = 95.62 - (3/100) = 95.59m
For offset peg P3
Required top of sight rail level = 95.90 + 2.00 = 97.90m
Actual of peg level = 97.12m
Therefore, distance above P3 = 0.78m
For offset peg P4
Required top of sight rail level = 95.59 + 2.00 = 97.59m
Actual of peg level = 96.75m
Therefore, distance above P4 = 0.84m

Setting out 12042018

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Setting out 12042018

Similar to Setting out 12042018 (20)

Recently uploaded

Recently uploaded (20)

Setting out 12042018